19 March 2012

Search For Personality Genes Comes Up Empty

In another case of missing heredity, a meta-analysis involving 20,000 Europeans in all, searching for SNPs linked to Big Five personality traits (extraversion, neuroticism, conscientiousness, openness to experience, and agreeableness) came up empty, despite twin studies showing up to a 50% hereditary component to personality and that shared environment has little impact on personality.

Color me unimpressed.

* There have been traits very akin to personality traits for which genetic connections have been identified (novelty seeking/impulsivity; inability to maintain long term relationships; resilience in the face of traumatic events; predisposition to substance abuse, etc.).

* There is even a subtype of ADHD associated with a particular identified gene and the definition of ADHD is closely aligned with the Big Five trait of conscientiousness.

* The Big Five are produces of subscores, and those subscores are known to differ materially between men and women with similar Big Five Scorees, so looking at the composite score includes inherent confounds in a simple statistical method.

* SNPs aren't the only way that a gene can be coded in the genome.

* The case that mental conditions linked to personality including a disposition towards anxiety and psychopathy (narrowly defined, not including all antisocial personality disorder) manifest very young and are very likely at least congenital is great.

In short, there is immense evidence that somewhere in the genome, or at least the epigenome there are codes for personality, and the fact that we can't find them using a particular, crude methodology for doing so doesn't mean that they don't exist. Maybe we just don't know what the genetic codes were are looking for would even look like.